Bündchen's $700 Taschen book released in celebration of her 20th year career sold out in one day, before hitting shelves.

In the late 1990s, Bündchen was the first in a wave of Brazilian Models to find international success. In 1999, Vogue noted "The Return of the Sexy Model", and she was credited with ending the "heroin chic" era of modeling. Bündchen was one of the Victoria's Secret Angels from 2000 until mid-2007. Bündchen pioneered the "horse walk", a stomping movement created when a model picks her knees up high and kicks her feet out in front. In a 2007 Vogue interview, Claudia Schiffer stated that Bündchen is the only remaining supermodel.

In 1993, Bündchen joined a modeling course with her sisters Patrícia and Gabriela at their mother's insistence. The following year, Bündchen was discovered by the Elite modeling agency at a shopping mall in São Paulo while on a school excursion. She was subsequently selected for a national contest, Elite Look of the Year, in which she placed second. Bündchen placed fourth in the Elite Model Look world contest in Ibiza, Spain. At 14, Bündchen moved to São Paulo to launch her modeling career. In 1996, Bündchen had her first New York City break at Fashion Week.

Bündchen travelled to London in 1997, where she auditioned for 42 shows. She got her big break when chosen for her ability to walk in towering heels on a slippery runway for Alexander McQueen's spring 1998 "rain" ready-to-wear show. Echoing similar accolades for Elle Macpherson a decade earlier, McQueen dubbed Bündchen "the Body", immediately boosting her bookings. In 1998, she posed for Missoni, Chloé, Dolce & Gabbana, Valentino, Gianfranco Ferré, Ralph Lauren, and Versace campaigns. She made the cover of the French edition of Vogue, and fashion magazine i-D featured her on its cover, profiling "A Girl Called Gisele." The Vogue online encyclopedia of Models states, "As the year 2000 approached, Gisele Bündchen was the world's hottest model, opening up a new category in the popular imagination: the Brazilian bombshell."

From 1998 to 1999, Bündchen dated American model Scott Barnhill. In 2000, she had a brief relationship with American actor Josh Hartnett. From 2000 to 2005, Bündchen was in a relationship with American actor Leonardo DiCaprio. In 2004, Bündchen and DiCaprio made People's annual Most Beautiful Couples List. Bündchen dated Brazilian businessman and polo player Rico Mansur for six months between 2002 and 2003, after Bündchen and DiCaprio broke up for the first time. In 2006, she dated American Surfer Kelly Slater.

She appeared on the cover of Vogue in July, November and December 1999. She won the VH1/Vogue Model of the Year for 1999, and a January 2000 cover gave her three consecutive Vogue covers. In 2000, she became the fourth model to appear on the cover of the music magazine Rolling Stone when she was named "The Most Beautiful Girl in the World". Bündchen has appeared on the covers of many top fashion magazines, including W, Harper's Bazaar, Elle, Allure, as well as style and lifestyle publications such as The Face, Arena, Citizen K, Flair, GQ, Esquire, and Marie Claire, and in the Pirelli Calendar in 2001 and 2006. She has also been seen in TIME, Vanity Fair, Forbes, Newsweek, and Veja. Bündchen has appeared on more than 1,200 magazine covers throughout the world. She simultaneously featured on the covers of both the US and British editions of Vogue in January 2000.

In 2000, Bündchen was dubbed the "Boobs from Brazil" for inspiring the 36,000 breast enhancement surgeries performed that year in Brazil. In 2006, Elle surveyed the American leading stylists and asked them to name the star whose hair was a favourite for their clients. More than 50 percent gave Bündchen the title of best hair in Hollywood. In February 2008, a survey by the International Society of Aesthetic Plastic Surgery (ISAPS) asked the question, "What influences do celebrities have on the decisions patients make"? The survey was sent to more than 20,000 plastic Surgeons in 84 countries. Bündchen was among the most frequently mentioned celebrities. Bündchen won the abdomen and hair categories and placed second in the breasts category. In 2008, a black-and-white photo of Bündchen, shot by Irving Penn, auctioned for $193,000 (£96,000). Bündchen's fetched by far the most on the night.

In November 2002, Bündchen was paid a reported £320,000 and given two black mink coats by American fur company Blackglama to head its new advertising campaign. Activists from PETA (People for the Ethical Treatment of Animals), invaded the runway during the Victoria's Secret show in New York and brandished placards saying "Gisele: fur scum". The Brazilian was one of the most prominent Models to wear fur since it began to come back into acceptability in fashion circles. A PETA spokesperson said: "By getting into bed with the fur-pushers, Gisele has become PETA enemy number one. Every time that Gisele or anyone else wears furs they are sentencing countless animals to a violent and cruel death."

Photographed by Steven Meisel, she was presented on the September 2004 cover of American Vogue as one of the "Models of the Moment". In 2004, Bündchen co-starred with Queen Latifah and Jimmy Fallon in the 2004 remake of Taxi. In 2005, she was chosen to wear the Victoria's Secret Fantasy Bra again, the Sexy Splendor Fantasy Bra. At the time, it was the second-most expensive bra ever made, valued at $12.5 million. In its December 2005 issue, New York magazine list Bundchen as No. 43 in its list of 123 reasons to love New York City.

Bündchen donated $150,000 to Brazil's Zero Hunger program. She designed a limited necklace edition for Harper's Bazaar, crafted by jewelers Gumuchian Fils. These necklaces were sold to raise money for St. Jude Children's Research Hospital. She contributed an autographed iPod loaded with a personal playlist to be auctioned off, with all proceeds benefiting Music Rising, a campaign founded in 2005 to replace lost or destroyed instruments of Musicians in the Gulf Coast Region after hurricane disasters.

In 2006, Bündchen became the face of American Express Red, part of the Product Red initiative. A portion of earnings from this credit card are donated to HIV/AIDS victims in Africa. In 2009, she appeared on 30 covers of the international issues of Elle wearing Product Red clothing and posing with products from companies who support the same cause.

In July 2007 Forbes named her the world's top-earning model. By 2008, she continued to dominate the Forbes list of the world's highest-earning Models, and appeared on the magazine's list of the Top 20 richest Women in Entertainment. During 2009–2010, she was the top earning supermodel.

In 2008 Bündchen and Brady dished out Turkey and all the trimmings unannounced to over 400 job trainees in Roxbury Massachusetts for Goodwill Industries International.

Bündchen began dating New England Patriots quarterback Tom Brady in December 2006. In 2009, Brady revealed they had been set up on a blind date by a mutual friend. Bündchen and Brady married on 26 February 2009 in a small Catholic ceremony at St. Monica Catholic Church in Santa Monica, California. In April 2009, the couple held a second marriage ceremony, in Costa Rica. Bündchen and Brady have two children, a son born in 2009 and a daughter born in 2012. She is also stepmother to Brady's first son from his previous relationship with Actress Bridget Moynahan, whom Brady had split with in December 2006. In 2010, Bündchen told Harper's Bazaar how important breastfeeding is for her. Bündchen and her family eat primarily a plant-based diet.

In 2010, she retained the top spot as Forbes's highest-earning model. In May 2011, Forbes ranked her as the world's top-earning model for the fifth consecutive time. Her earnings climbed over the previous year, thanks to an economic boom in Brazil, coupled with a 10 per cent surge in the value of the Brazilian real against the dollar. Also in 2013 she ranked No. 3 on the 16 most successful female entrepreneurs list by Forbes.

In August 2011, Bündchen ranked 60th on the Forbes list of The World's 100 Most Powerful Women. She ranked third on The 20 Youngest Power Women of 2011 List at age 31. In 2011 Forbes named Bündchen and Brady as the World's Highest Paid Celebrity couple, beating Brad Pitt and Angelina Jolie as well as Beyoncé and Jay-Z. In August 2012 she was one of four people in the fashion industry and the only model to be ranked on the Forbes list of "The World's Most Powerful Women" at No. 83. She ranked in the top 10 of the Forbes list of "Entertainment's Highest-Paid Women" in 2012, at No. 8.

In January 2012, Bündchen visited Kenya on a goodwill mission to improve Energy poverty. She spent a day with a family in a village in Kisumu County and helped them with tasks such as carrying firewood to their hut – while discussing the dangers of using firewood inside homes that do not have Energy. She danced with the locals and visited various homes, as well as teaming up with UK NGO Practical Action during the course of her stay. In April 2012 she donated money for AIDS research. On the eve of World Environment Day 4 June 2012, Bündchen, who is Goodwill Ambassador of the UNEP (United Nations Environment Programme), went to Rio de Janeiro to plant the first of a series of 50,000 trees in a degraded area.

Bündchen, however, disputes the number, telling WSJ. magazine in November 2013, "Who are they speaking to when they come up with these numbers? Not my accountant, that's for sure."

In January 2014, Bündchen joined the Rainforest Alliance board of Directors.

In May 2015, Brazilian magazine Istoe Gente reported that Bündchen's line of INtimates, Gisele Bundchen INtimates has been lucrative. "As of May 2015 especially in e-commerce, it was recorded to have an increase of 181% in one year. We went from 30,000 visitors per month to 100,000," says Vanda Dias, e-commerce manager for Hope, which manages the top brand.

Forbes estimated Bündchen's 2016 income at $30.5 million.

Bündchen's jelly sandals Ipanema by Gisele Bundchen sell as much as 25 million pairs annually and accounted for more than 60% of Grendene’s annual exports of about $250 million in 2013.